In many mechanical assemblies, one part is attached to another with an interference fit, also known as a press fit, friction fit, or jam fit. For example, a cylindrical shaft is press fitted with a component such as a bearing, impeller, gear, wheel or the like, which is mounted to rotate with the shaft. Similarly, many mechanical assemblies comprise arrangements wherein a component such as a bearing, race, seal, or the like is press fitted around its periphery to an opening in a housing, usually to encircle a shaft or the like extending through the opening of the housing. Typically the removal of such components from a shaft or housing for repair or replacement is problematic and requires use of a puller or similar tool.
Many types of pullers are available. Often the pulling devices are special-purpose devices that are designed to provide an “outside pull.” In an outside pull, various clamping arms grip around the outside of an element, such as a pulley, and are then used to pull that element off of a shaft or the like. An “inside pull” is an alternative procedure that is effected by means of arms that have gripping ends that extend radially outwardly so as to engage the inside surface of an annular element such as a bushing or bearing for removal from a housing or sleeve, for example.
Therefore, it is desirable that a puller is adjustable to enable pulling or removal of elements having various inside or outside diameters.
It is desirable that a puller be reversible so as to provide both an inside as well as an outside pull.
It is desirable that a puller uniformly engages the element and locks onto or otherwise remains centered on the element during pulling to prevent the puller from disengaging and from damaging the element or surrounding parts. For example, U.S. Pat. No. 4,007,535 discloses a pulling device wherein the pulling arms, once positioned around an element, are locked into that position so that they cannot slip from the element which is being pulled
It is desirable that the engaging faces maintain a predetermined relative angle, even with size adjustment, so as spread the pulling force over a large area so as to not damage the element due to excessive pressure at points. This quality is particularly important when engaging in an inside pull of a seal when the seal is to be reused.
Thus, there has developed an increased need for pulling devices that are flexible and may be used not only for inside pulls but also for outside pulls upon elements of varying diameter. Also such a pulling mechanism may desirably be locked into a specific diameter in either the inside or outside pull position. Also, desirably, the puller's surfaces that engage the element remain at a predetermined angle to the element regardless of size adjustment. Seeking such a construction has led to the development of the present invention.